< DOE = 60 => <AOB/2 + < BOC/2 = 60 =>(fiindcă <BOC = 5AOB)
<AOB/2 + 5AOB/2 = 60
6<AOB/2 = 60 =>
<AOB = 2*60/6
<AOB = 20
<BOC = 5<AOB
<BOC = 5 * 20
< BOC = 100
<AOC = <AOB + <BOC
<AOC = 20 + 100
<AOC = 120